A method, system, device and medium for pre-processing projection data of a CT scanning device

Abstract

The application provides a kind of projection data pre-processing method, system, device and medium of CT scanning equipment, comprising: presetting multiple reference energy values, so that CT scanning equipment scans air multiple times to obtain multiple reference projection data corresponding to any reference energy value, obtain reference projection average value corresponding to any reference energy value, and form a reference list, the reference list includes the correspondence between multiple reference energy values and multiple reference projection average values;According to the actual energy value of the scanning site scanned by the CT scanning equipment, obtain the reference energy value corresponding to the actual energy value in the reference list, obtain the normalization base according to the reference projection average value corresponding to the reference energy value, and normalize the actual projection data of multiple angles scanned by the CT scanning equipment on the detection site. After adopting the scheme of the present application, it is not necessary to set a reference channel, the limitation on patient positioning is reduced, and no artifacts will be generated when the detector edge channel is blocked.

Description

Technical Field

[0001] This invention relates to the field of medical image processing, and in particular to a method, system, device, and medium for preprocessing projection data from a CT scanning device. Background Technology

[0002] During CT scans, instability in the performance of the X-ray tube or radiation damage to the detector crystal can lead to inconsistent data across different channels and angles. Therefore, data normalization is necessary.

[0003] Existing technologies typically use a reference channel located outside the scanning field of view for normalization. However, the reference channel can sometimes be obstructed by medical devices on the scanning bed or by the patient's own arm. In such cases, the value of the reference channel changes significantly with the projection angle and the projected information. Using it as the normalization value will result in step-like artifacts in the coronal and sagittal images. Summary of the Invention

[0004] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a method, system, device and medium for preprocessing projection data of CT scanning equipment.

[0005] This invention discloses a method for preprocessing projection data from a CT scanning device, comprising the following steps:

[0006] Multiple reference energy values ​​are preset, and the reference current value and reference exposure time corresponding to any one of the reference energy values ​​are used to make the CT scanning device scan the air multiple times to obtain multiple reference projection data corresponding to any one of the reference energy values;

[0007] The average value of multiple reference projection data corresponding to any one of the reference energy values ​​is calculated to obtain the average reference projection value corresponding to any one of the reference energy values, and a reference list is formed, wherein the reference list contains the correspondence between multiple reference energy values ​​and multiple average reference projection values;

[0008] Based on the actual current value and actual integration time of the CT scanning device scanning the area to be examined, the actual energy value is calculated and obtained. The reference energy value corresponding to the actual energy value is obtained from the reference list. The normalization base is obtained based on the average value of the reference projection corresponding to the reference energy value. The actual projection data of the CT scanning device scanning multiple angles of the area to be examined are normalized.

[0009] Preferably, obtaining the normalized cardinality includes:

[0010] Obtain a reference energy value from the reference list that is equal to the actual energy value, and use the average value of the reference projection corresponding to the reference energy value as the normalization base.

[0011] Preferably, obtaining the normalized cardinality includes:

[0012] Multiple reference energy values ​​that are close to the actual energy value are obtained from the reference list. Interpolation is performed using the average value of multiple reference projections corresponding to the multiple reference energy values ​​to obtain a predicted projection average value as the normalization base.

[0013] Preferably, the step of having the CT scanning device perform multiple scans of the air further includes:

[0014] The background noise of the CT scanning device is removed from the reference projection data collected in each scan.

[0015] The present invention also discloses a projection data preprocessing system for a CT scanning device, including an acquisition module and a normalization module;

[0016] The acquisition module presets multiple reference energy values, and uses the reference current value and reference exposure time corresponding to any one of the reference energy values ​​to make the CT scanning device scan the air multiple times to obtain multiple reference projection data corresponding to any one of the reference energy values;

[0017] The acquisition module calculates the average value of multiple reference projection data corresponding to any one of the reference energy values, obtains the average reference projection value corresponding to any one of the reference energy values, and forms a reference list, which contains the correspondence between multiple reference energy values ​​and multiple average reference projection values.

[0018] The normalization module calculates the actual energy value based on the actual current value and actual integration time of the CT scanning device scanning the area to be examined, obtains the reference energy value corresponding to the actual energy value from the reference list, obtains the normalization base based on the average value of the reference projection corresponding to the reference energy value, and normalizes the actual projection data of any angle of the area to be examined scanned by the CT scanning device.

[0019] The present invention also discloses an electronic device, which includes a memory storing computer-executable instructions and a processor, wherein when the instructions are executed by the processor, the electronic device performs the aforementioned projection data preprocessing method of a CT scanning device.

[0020] The present invention also discloses a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is run on a computer, it causes the computer to perform the aforementioned projection data preprocessing method of the CT scanning device.

[0021] Compared with existing technologies, the above technical solution has the following advantages: no reference channel is required, reducing restrictions on patient positioning, and no artifacts are generated when the detector edge channel is blocked. Attached Figure Description

[0022] Figure 1 A schematic flowchart of the projection data preprocessing method for a CT scanning device provided by the present invention;

[0023] Figure 2 The image is a reconstructed image processed by the projection data preprocessing method provided by the present invention. Detailed Implementation

[0024] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0026] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0027] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0028] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0030] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0031] like Figure 1 As shown, this invention discloses a method for preprocessing projection data of a CT scanning device, comprising the following steps:

[0032] S100: Multiple reference energy values ​​are preset. The reference current value and reference exposure time corresponding to any reference energy value are used to make the CT scanning device scan the air multiple times to obtain multiple reference projection data corresponding to any reference energy value.

[0033] Specifically, multiple reference energy values ​​are preset, based on E i =A i T i Using reference energy value E i The corresponding reference current value A i Compared with the reference exposure time T i This allows the CT scanner to scan the air multiple times; that is, it uses current A. i Multiple exposures of air were performed using milliamperes, with each exposure lasting for T seconds. i Seconds, obtain the reference energy value E i The corresponding multiple reference projection data.

[0034] S200. Calculate the average value of multiple reference projection data corresponding to any reference energy value, obtain the average value of reference projection corresponding to any reference energy value, and form a reference list. The reference list contains the correspondence between multiple reference energy values ​​and multiple average values ​​of reference projection.

[0035] Specifically, for the reference energy value E i The reference energy value E is obtained by averaging the corresponding multiple reference projection data. i The corresponding reference projection average value M i Through steps S100 to S200, the average reference projection values ​​corresponding to multiple reference energy values ​​are obtained, and a reference list recording the above correspondences is formed.

[0036] S300. Based on the actual current value and actual integration time of the CT scanning device scanning the area to be examined, calculate the actual energy value, obtain the reference energy value corresponding to the actual energy value from the reference list, obtain the normalization base based on the average reference projection value corresponding to the reference energy value, and normalize the actual projection data of the CT scanning device scanning multiple angles of the area to be examined.

[0037] Specifically, for the actual projection data of the patient's examination site from multiple angles, the actual current value A and the actual integration time T during scanning are obtained, and the actual energy value E is calculated. v =AT. Obtain the actual energy value E from the reference list. v The normalized base R is obtained from the reference energy value corresponding to the reference projection average value. v Using the normalized base R v Normalize the actual projection data from multiple angles.

[0038] Preferably, obtaining the normalized cardinality includes:

[0039] Obtain a reference energy value from the reference list that is equal to the actual energy value, and use the average value of the reference projection corresponding to the reference energy value as the normalization base.

[0040] Specifically, obtain the actual energy value E from the reference list. v E reference energy values ​​of equal magnitude i Using reference energy value E i The corresponding reference projection average value M i As the normalization base R v The actual projection data I at a certain angle v Normalization is performed to obtain the normalized actual projection data for that angle. The above normalization process was performed on the actual projection data for all angles.

[0041] Preferably, obtaining the normalized cardinality includes:

[0042] Multiple reference energy values ​​that are close to the actual energy value are obtained from the reference list. The average value of multiple reference projections corresponding to the multiple reference energy values ​​is used for interpolation to obtain a predicted projection average value as the normalization base.

[0043] Specifically, obtain the actual energy value E from the reference list. v Multiple reference energy values ​​of equal magnitude, such as reference energy value E1, reference energy value E2, and reference energy value E3, are interpolated using the reference projection average values ​​M1, M2, and M3 corresponding to these multiple reference energy values ​​to obtain a predicted projection average value M. p As the normalization base R v For actual projection data I v Normalization is performed to obtain the normalized actual projection data. The above normalization process was performed on the actual projection data for all angles.

[0044] Preferably, the step of having the CT scanning device perform multiple scans of the air further includes:

[0045] Background noise from the CT scanning equipment is removed from the reference projection data acquired in each scan.

[0046] See Figure 2 , Figure 2 (a) is the reconstructed image obtained after preprocessing using the detector's edge channel values ​​as the normalization base when the detector's edge channels are blocked. This image exhibits obvious step-like artifacts; while Figure 2 (b) is the reconstructed image obtained after preprocessing using the projection data preprocessing method of the present invention, which finds the corresponding projection average value from the reference list as the normalization base. This image is similar to... Figure 2 Compared to (a), the number and intensity of step artifacts are significantly reduced, and the image quality is significantly improved.

[0047] The present invention also discloses a projection data preprocessing system for a CT scanning device, including an acquisition module and a normalization module;

[0048] The acquisition module presets multiple reference energy values. Using the reference current value and reference exposure time corresponding to any reference energy value, the CT scanning device scans the air multiple times to obtain multiple reference projection data corresponding to any reference energy value.

[0049] The acquisition module calculates the average value of multiple reference projection data corresponding to any reference energy value, obtains the average value of reference projection corresponding to any reference energy value, and forms a reference list containing the correspondence between multiple reference energy values ​​and multiple average values ​​of reference projection.

[0050] The normalization module calculates the actual energy value based on the actual current value and actual integration time of the CT scanner scanning the area to be examined. It then obtains the reference energy value corresponding to the actual energy value from the reference list and obtains the normalization base based on the average value of the reference projection corresponding to the reference energy value. Finally, it normalizes the actual projection data of any angle of the area to be examined scanned by the CT scanner.

[0051] The present invention also discloses an electronic device, which includes a memory storing computer-executable instructions and a processor, wherein when the instructions are executed by the processor, the electronic device performs the aforementioned projection data preprocessing method of a CT scanning device.

[0052] The present invention also discloses a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is run on a computer, it causes the computer to perform the aforementioned projection data preprocessing method of the CT scanning device.

[0053] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preprocessing projection data of a CT scanning device, characterized in that, Includes the following steps: Multiple reference energy values ​​are preset, and the reference current value and reference exposure time corresponding to any one of the reference energy values ​​are used to make the CT scanning device scan the air multiple times to obtain multiple reference projection data corresponding to any one of the reference energy values; The average value of multiple reference projection data corresponding to any one of the reference energy values ​​is calculated to obtain the average reference projection value corresponding to any one of the reference energy values, and a reference list is formed, wherein the reference list contains the correspondence between multiple reference energy values ​​and multiple average reference projection values; Based on the actual current value and actual integration time of the CT scanning device scanning the area to be examined, the actual energy value is calculated and obtained. The reference energy value corresponding to the actual energy value is obtained from the reference list. The normalization base is obtained based on the average value of the reference projection corresponding to the reference energy value. The actual projection data of the CT scanning device scanning multiple angles of the area to be examined are normalized.

2. The projection data preprocessing method according to claim 1, characterized in that, The process of obtaining the normalized cardinality includes: Obtain a reference energy value from the reference list that is equal to the actual energy value, and use the average value of the reference projection corresponding to the reference energy value as the normalization base.

3. The projection data preprocessing method according to claim 1, characterized in that, The process of obtaining the normalized cardinality includes: Multiple reference energy values ​​that are close to the actual energy value are obtained from the reference list. Interpolation is performed using the average value of multiple reference projections corresponding to the multiple reference energy values ​​to obtain a predicted projection average value as the normalization base.

4. The projection data preprocessing method according to claim 1, characterized in that, The method of having the CT scanning device perform multiple scans of the air further includes: The background noise of the CT scanning device is removed from the reference projection data collected in each scan.

5. A projection data preprocessing system for a CT scanning device, characterized in that, It includes an acquisition module and a normalization module; the acquisition module presets multiple reference energy values, and uses the reference current value and reference exposure time corresponding to any one of the reference energy values ​​to make the CT scanning device scan the air multiple times to obtain multiple reference projection data corresponding to any one of the reference energy values; The acquisition module calculates the average value of multiple reference projection data corresponding to any one of the reference energy values, obtains the average reference projection value corresponding to any one of the reference energy values, and forms a reference list, which contains the correspondence between multiple reference energy values ​​and multiple average reference projection values. The normalization module calculates the actual energy value based on the actual current value and actual integration time of the CT scanning device scanning the area to be examined, obtains the reference energy value corresponding to the actual energy value from the reference list, obtains the normalization base based on the average value of the reference projection corresponding to the reference energy value, and normalizes the actual projection data of any angle of the area to be examined scanned by the CT scanning device.

6. An electronic device, characterized in that, The electronic device includes a memory storing computer-executable instructions and a processor, which, when executed by the processor, cause the electronic device to perform the projection data preprocessing method of the CT scanning device according to any one of claims 1-4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run on a computer, it causes the computer to perform the projection data preprocessing method of the CT scanning device according to any one of claims 1-4.

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